Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 814
Filter
2.
Eur J Pain ; 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38623029

ABSTRACT

BACKGROUND AND OBJECTIVE: Recently, a consensus process specified a core outcome set (COS) of domains to be assessed in each comparative effectiveness research and clinical practice related to acute postoperative pain. Physical function (PF) was one of these domains. The aim of this review was to investigate which patient-reported outcome measures (PROMs) are used to assess PF after total knee arthroplasty (TKA) in clinical trials and if they fulfil basic requirements for a COS of PROMs based on their psychometric properties. METHODS: A systematic review of randomized controlled trials and observational studies based on a search in MEDLINE, EMBASE and CENTRAL was undertaken. PROMs and performance measures were extracted and investigated, including evaluation of psychometric properties of PROMs based on COSMIN recommendations. RESULTS: From initially 2896 identified records, 479 studies were included in the qualitative synthesis. Only 87 of these trials (18%) assessed PF using PROMs, whereas especially performance outcome measures were used in 470 studies (98%). Application of the 'COSMIN Risk-of-Bias-Box 1' to 13 of the 14 identified PROMs resulted in insufficient content validity of the included PROMs regarding the target population based on the inauguration or development articles. CONCLUSION: Our data indicate that a patient-centred postoperative assessment of PF in pain-related clinical trials early after TKA is not common, even though patient-reported assessment is widely recommended. In addition, none of the applied PROMs shows content validity based on their inauguration or development articles for the assessment of postoperative pain-related PF after TKA. SIGNIFICANCE: A systematic search for patient-reported outcome measures assessing postoperative, pain-related physical function after total knee arthroplasty in clinical trials and assessment of their content validity revealed none that fulfilled requirements based on COSMIN recommendations.

3.
J Heart Lung Transplant ; 40(5): 368-376, 2021 05.
Article in English | MEDLINE | ID: mdl-33642140

ABSTRACT

BACKGROUND: The size of the Fontan population with end-stage heart failure is growing. In this population, heart transplantation has been the only option. This study sought to investigate the efficacy of ventricular assist device (VAD) support in Fontan patients. METHODS: We conducted a retrospective study of Fontan patients in the Advanced Cardiac Therapies Improving Outcomes Network. We evaluated patient characteristics, and the clinical and physiologic outcomes after VAD implantation. RESULTS: We identified 45 Fontan patients implanted with VAD. The average age of patients was 10 years (interquartile range: 4.5-18) and 30% were female. The majority had a morphologic right ventricle (69%), moderate or greater ventricular dysfunction (83%), and moderate or greater atrioventricular valve regurgitation (65%). The majority of implants were as a bridge to transplantation (76%), and the majority of patients were Interagency Registry for Mechanically Assisted Circulatory Support Profile 2 (56%). The most commonly employed device was the Medtronic HeartWare HVAD (56%). A total of 13 patients were discharged on device support, and 67% of patients experienced adverse events, the most common of which were neurologic (25%). At 1 year after device implantation, the rate of transplantation was 69.5%, 9.2% of patients continued to be VAD supported, and 21.3% of patients had died. Hemodynamically, VAD was effective in decreasing both Fontan and ventricular end-diastolic pressures in some individuals. CONCLUSIONS: VAD is effective in supporting patients with end-stage Fontan failure awaiting heart transplantation. Future research should focus on identifying clinical and physiologic characteristics predictive of a favorable response to VAD support.


Subject(s)
Fontan Procedure , Heart Failure/surgery , Heart-Assist Devices , Registries , Adolescent , Child , Child, Preschool , Female , Follow-Up Studies , Heart Transplantation , Humans , Male , Retrospective Studies , Treatment Outcome
4.
Skeletal Radiol ; 50(8): 1717-1721, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33517510

ABSTRACT

COVID-19 has presented with a variety of manifestations including peripheral neurological symptoms. The most commonly associated peripheral neuropathies described with COVID-19 are Guillain-Barre syndrome and its variants as well as critical illness polyneuropathy. We report in this paper the distinct MRI findings of an unusual case of peripheral neuropathy associated with COVID-19. These findings are similar to those seen in Guillain-Barre syndrome or one of its variants, although differing from the classic condition in certain key clinical and radiological features.


Subject(s)
COVID-19 , Peripheral Nervous System Diseases , Humans , Muscle Denervation , Muscular Atrophy/diagnostic imaging , Peripheral Nervous System Diseases/diagnostic imaging , SARS-CoV-2
5.
Orthopade ; 48(10): 844-848, 2019 Oct.
Article in German | MEDLINE | ID: mdl-31041462

ABSTRACT

BACKGROUND AND OBJECTIVE: Thoracic spinal stenosis is characterized by a reduction in the volume of the thoracic spinal canal, leading to compromise of the spinal cord or nerve roots. This article provides an overview of the known etiology, pathogenesis, diagnostic algorithm, and treatment of thoracic spinal stenosis. MATERIALS AND METHODS: This paper is based on an overview of the literature from the past 25 years as well as the authors' own experience and results. RESULTS AND CONCLUSION: Thoracic spinal stenosis is a rare entity, for which the incidence is unknown. Pathoanatomically, the stenosis is caused by ligament or facet joint hypertrophy. Ventral stenosis can be caused by broad-based thoracic disc protrusion and ossification of the posterior longitudinal ligament (OPLL). Depending on location, main symptoms are pain and, in advanced cases, myelopathic symptoms which spare the upper extremities. Surgical decompression with or without instrumentation is the only treatment option. We present a cohort of 9 patients operated in a time frame of 7 years using a ventral approach, 89% of whom reported a substantial reduction in pain.


Subject(s)
Ossification of Posterior Longitudinal Ligament , Spinal Cord Compression , Spinal Stenosis , Thoracic Vertebrae/surgery , Decompression, Surgical , Humans , Spinal Stenosis/etiology , Spinal Stenosis/pathology , Spinal Stenosis/surgery , Treatment Outcome
6.
Science ; 364(6436)2019 04 12.
Article in English | MEDLINE | ID: mdl-30975859

ABSTRACT

The neurobiological mechanisms underlying the induction and remission of depressive episodes over time are not well understood. Through repeated longitudinal imaging of medial prefrontal microcircuits in the living brain, we found that prefrontal spinogenesis plays a critical role in sustaining specific antidepressant behavioral effects and maintaining long-term behavioral remission. Depression-related behavior was associated with targeted, branch-specific elimination of postsynaptic dendritic spines on prefrontal projection neurons. Antidepressant-dose ketamine reversed these effects by selectively rescuing eliminated spines and restoring coordinated activity in multicellular ensembles that predict motivated escape behavior. Prefrontal spinogenesis was required for the long-term maintenance of antidepressant effects on motivated escape behavior but not for their initial induction.


Subject(s)
Antidepressive Agents/pharmacology , Dendritic Spines/drug effects , Depressive Disorder/physiopathology , Ketamine/pharmacology , Prefrontal Cortex/drug effects , Stress, Psychological/physiopathology , Synapses/drug effects , Animals , Antidepressive Agents/therapeutic use , Corticosterone/pharmacology , Dendritic Spines/pathology , Dendritic Spines/physiology , Depressive Disorder/chemically induced , Depressive Disorder/drug therapy , Disease Models, Animal , Escape Reaction/drug effects , Ketamine/therapeutic use , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neuronal Plasticity/drug effects , Prefrontal Cortex/pathology , Prefrontal Cortex/physiopathology , Stress, Psychological/chemically induced , Synapses/physiology
7.
Brain Topogr ; 32(2): 283-285, 2019 03.
Article in English | MEDLINE | ID: mdl-30426267

ABSTRACT

Acute pain from mucositis in patients with head and neck cancer (HNC) undergoing radiation therapy (RT) is common, and may not respond well to narcotics. We used low resolution electromagnetic tomography z-score neurofeedback (LFBz) to investigate whether patients could modify brain wave activity associated with acute pain and whether this would reduce the experience of pain. HNC patients scheduled for RT had baseline pre-pain onset measures (EEG and numeric rating scale) collected before RT and then at pain onset before using analgesics, after each LFBz session and at the end of RT. Up to six sessions of LFBz training were offered over the remaining RT. Up to six 20-min sessions of LFBz were offered over the remaining RT. Data were collected before and after each LFBz session and at the end of RT. Seventeen patients recruited; fourteen were treated and reported decreased pain perception. LFBz allowed patients to modify their brain activity in predesignated areas of the pain matrix toward the direction of their baseline, pre-pain condition (including Brodmann areas (BAs) 3, 4, 5, 13, 24, and 33). LFBz can modify brain regions relevant for pain and these changes were associated with self-reported decreases in pain perception.


Subject(s)
Acute Pain/etiology , Head and Neck Neoplasms/complications , Magnetic Resonance Imaging/methods , Neurofeedback , Pain Management/methods , Electroencephalography , Female , Humans , Male , Middle Aged , Pain Measurement , Treatment Outcome
8.
Gait Posture ; 58: 358-362, 2017 10.
Article in English | MEDLINE | ID: mdl-28866455

ABSTRACT

Residual deformity of the femoral head after slipped capital femoral epiphysis (SCFE) may be accompanied by a loss of femoral offset and lead to femoro-acetabular impingement (FAI), especially during hip flexion. It is hypothesized that during phases of the gait cycle, when the hip is flexed, the offset-loss is compensated by an increased external rotation. The gait pattern of 36 patients suffering from SCFE, who were treated by pinning-in-situ, were compared to a control group of 40 healthy adults by an instrumented 3D-gait analysis. Total patient group was subdivided into 3 subgroups in dependence on the offset (offset groups (OG)) quantified by the angle α according to Nötzli: OG1: α-angle <55°, OG2: α-angle between 55 and 75°, OG3: α-angle >75°. Comparisons were made at 3 instants: initial foot contact (0% gait cycle (GC)), 40-60% GC and 90-100% GC. Patients showed an increased external hip rotation during all 3 periods of the GC with a tendency of increasing external rotation in association with offset-loss. Only during hip extension (40-60% GC) there was a weak correlation between angle α and hip rotation (r=-0.375, p=0.024). In conclusion, the offset-loss does not lead to a functional relevant impingement during walking which needs compensation strategies like increasing external rotation during periods of hip flexion.


Subject(s)
Femoracetabular Impingement/physiopathology , Gait/physiology , Movement Disorders/etiology , Slipped Capital Femoral Epiphyses/physiopathology , Adult , Female , Femoracetabular Impingement/complications , Femoracetabular Impingement/diagnosis , Humans , Imaging, Three-Dimensional , Male , Movement Disorders/physiopathology , Slipped Capital Femoral Epiphyses/complications , Slipped Capital Femoral Epiphyses/diagnosis , Young Adult
9.
Dev Biol ; 426(2): 360-373, 2017 06 15.
Article in English | MEDLINE | ID: mdl-27471010

ABSTRACT

Unlike adult mammals, adult frogs regrow their optic nerve following a crush injury, making Xenopus laevis a compelling model for studying the molecular mechanisms that underlie neuronal regeneration. Using Translational Ribosome Affinity Purification (TRAP), a method to isolate ribosome-associated mRNAs from a target cell population, we have generated a transcriptional profile by RNA-Seq for retinal ganglion cells (RGC) during the period of recovery following an optic nerve injury. Based on bioinformatic analysis using the Xenopus laevis 9.1 genome assembly, our results reveal a profound shift in the composition of ribosome-associated mRNAs during the early stages of RGC regeneration. As factors involved in cell signaling are rapidly down-regulated, those involved in protein biosynthesis are up-regulated alongside key initiators of axon development. Using the new genome assembly, we were also able to analyze gene expression profiles of homeologous gene pairs arising from a whole-genome duplication in the Xenopus lineage. Here we see evidence of divergence in regulatory control among a significant proportion of pairs. Our data should provide a valuable resource for identifying genes involved in the regeneration process to target for future functional studies, in both naturally regenerative and non-regenerative vertebrates.


Subject(s)
Eye Proteins/biosynthesis , Gene Expression Regulation , Nerve Regeneration/physiology , Nerve Tissue Proteins/biosynthesis , Optic Nerve Injuries/physiopathology , Xenopus Proteins/biosynthesis , Xenopus laevis/genetics , Amino Acid Sequence , Animals , Animals, Genetically Modified , Eye Proteins/genetics , Gene Ontology , Molecular Sequence Annotation , Nerve Crush , Nerve Tissue Proteins/genetics , RNA, Messenger/genetics , RNA, Messenger/isolation & purification , Retinal Ganglion Cells/metabolism , Ribosomes/metabolism , Sequence Alignment , Sequence Analysis, RNA , Sequence Homology, Amino Acid , Signal Transduction , Xenopus Proteins/genetics , Xenopus laevis/physiology
10.
Support Care Cancer ; 23(12): 3465-72, 2015 Dec.
Article in English | MEDLINE | ID: mdl-25791393

ABSTRACT

BACKGROUND: Head and neck cancer (HNC) patients can experience symptoms due to the tumor itself or to the treatment, with an impact on health-related quality of life (HRQoL). Patient-reported outcome (PRO) measures pertaining to HRQoL are used in medical research and to support clinical decisions. PRO instrument applicability and cultural adaptation must be tested for each population. The aim of this study is to linguistically validate the Italian translation of the M.D. Anderson Symptom Inventory--Head and Neck Module (MDASI-HN). METHODS: Following forward and backward translation of the items of the English MDASI-HN into Italian, it was administered along with a cognitive debriefing to HNC patients able to read and understand Italian language. Individual and group responses are presented using descriptive statistics. RESULTS: From May 2013 through September 2013, 56 patients with HNC (18 during curative treatment, 20 in palliative chemotherapy, and 18 in follow-up period) completed the MDASI-HN followed by accompanying cognitive debriefing. Ninety-nine percent of the individual MDASI-HN items were completed. Average time to complete the MDASI-HN was 8.5 min (range 3-15). Results suggested overall ease of completion, relevance, and comprehensibleness of this translated self-report instrument in this Italian patient population. CONCLUSIONS: The Italian version of the MDASI-HN is linguistically valid; future research should explore dimensionality, reliability, and convergent, discriminant, and predictive validity of this patient-reported instrument, in order to use this translated version in outcomes research and clinical settings.


Subject(s)
Head and Neck Neoplasms/therapy , Language , Symptom Assessment/methods , Translations , Adolescent , Adult , Aged , Aged, 80 and over , Female , Head and Neck Neoplasms/diagnosis , Head and Neck Neoplasms/pathology , Humans , Italy , Linguistics/methods , Male , Middle Aged , Outcome Assessment, Health Care/methods , Outcome Assessment, Health Care/standards , Patient Outcome Assessment , Quality of Life , Reproducibility of Results , Self Report , Symptom Assessment/standards , Symptom Assessment/trends , Young Adult
11.
J Minim Invasive Gynecol ; 22(6S): S134, 2015.
Article in English | MEDLINE | ID: mdl-27678731
12.
Nat Mater ; 11(8): 690-3, 2012 Jun 10.
Article in English | MEDLINE | ID: mdl-22683821

ABSTRACT

Replacing noble metals in heterogeneous catalysts by low-cost substitutes has driven scientific and industrial research for more than 100 years. Cheap and ubiquitous iron is especially desirable, because it does not bear potential health risks like, for example, nickel. To purify the ethylene feed for the production of polyethylene, the semi-hydrogenation of acetylene is applied (80 × 10(6) tons per annum; refs 1-3). The presence of small and separated transition-metal atom ensembles (so-called site-isolation), and the suppression of hydride formation are beneficial for the catalytic performance. Iron catalysts necessitate at least 50 bar and 100 °C for the hydrogenation of unsaturated C-C bonds, showing only limited selectivity towards semi-hydrogenation. Recent innovation in catalytic semi-hydrogenation is based on computational screening of substitutional alloys to identify promising metal combinations using scaling functions and the experimental realization of the site-isolation concept employing structurally well-ordered and in situ stable intermetallic compounds of Ga with Pd (refs 15-19). The stability enables a knowledge-based development by assigning the observed catalytic properties to the crystal and electronic structures of the intermetallic compounds. Following this approach, we identified the low-cost and environmentally benign intermetallic compound Al(13)Fe(4) as an active and selective semi-hydrogenation catalyst. This knowledge-based development might prove applicable to a wide range of heterogeneously catalysed reactions.

13.
AJNR Am J Neuroradiol ; 32(8): 1532-8, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21757532

ABSTRACT

BACKGROUND AND PURPOSE: Radiographic determination of viable disease in cervical adenopathy following RT for head and neck cancer can be challenging. The purpose of this study was to evaluate the utility of US, with or without FNA, in regard to the postradiotherapy effects on documented metastatic adenopathy in patients with oropharyngeal cancer. MATERIALS AND METHODS: This study included 133 patients with node-positive oropharyngeal cancer who were irradiated from 1998 to 2004. Sonographic evaluation was performed within 6 months of completion of radiation. Posttreatment US results were compared with pretreatment CT images and were recorded as the following: progression, suspicious, indeterminate, posttreatment change, or regression (positive) versus nonsuspicious or benign (negative). FNAC was classified as nondiagnostic, negative, indeterminate, or positive. Results of US and US-guided FNAC were correlated with findings at neck dissection and disease outcome. RESULTS: Of 203 sonographic examinations, 90% were technically feasible and yielded a nonequivocal imaging diagnosis. Of 87 US-guided FNAs, 71% yielded a nonequivocal tissue diagnosis. The PPV and NPV of initial posttreatment US were 11% and 97%. Sensitivity and specificity were 92% and 28%. The PPV and NPV of US-guided FNA were 33% and 95%, and the sensitivity and specificity were 75% and 74%. On serial sonographic surveillance, of 33 patients with nonsuspicious findings, only 1 (3%) had neck recurrence. Of 22 patients with questionable findings on CT and negative findings on US, none had a neck recurrence. CONCLUSIONS: In experienced hands, serial US is an inexpensive noninvasive reassuring follow-up strategy after definitive head and neck RT, even when CT findings are equivocal.


Subject(s)
Neck/diagnostic imaging , Oropharyngeal Neoplasms/radiotherapy , Adult , Aged , Aged, 80 and over , Biopsy, Fine-Needle , Female , Humans , Lymphatic Metastasis , Male , Middle Aged , Neck/pathology , Oropharyngeal Neoplasms/pathology , Retrospective Studies , Ultrasonography
14.
Adv Exp Med Biol ; 669: 231-4, 2010.
Article in English | MEDLINE | ID: mdl-20217355

ABSTRACT

In 18 healthy age- and sex- matched controls and 13 patients with Wilsons disease (18-50 years) under continuous copper chelating therapy sinusoidal forearm movements of a given target rates (target rates: 0.2, 0.3, 0.4, 0.5, 0.6 Hz) as well as breathing movements were recorded by means of a goniometer and a breathing girdle in parallel. Additionally, controls and patients had to perform spontaneous forearm movements at their most comfortable rate. The percentage of time during which forearm and breathing movements were coupled was significantly reduced in the patients. With increasing target rate the mean breathing rate significantly increased in the controls but not in the patients. Furthermore, the variability of breathing rate significantly increased in the patients but not in the controls. These two factors probably caused that the coupling of breathing and extremity movements was significantly reduced in the patients.


Subject(s)
Movement/physiology , Music , Periodicity , Respiration , Adolescent , Adult , Aged , Case-Control Studies , Female , Hepatolenticular Degeneration/physiopathology , Humans , Male , Middle Aged , Young Adult
15.
J Evol Biol ; 23(4): 805-16, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20210826

ABSTRACT

Hybrid speciation is thought to be facilitated by escape of early generation hybrids into new habitats, subsequent environmental selection and adaptation. Here, we ask whether two homoploid hybrid plant species (Helianthus anomalus, H. deserticola) diverged sufficiently from their ancestral parent species (H. annuus, H. petiolaris) during hybrid speciation so that they are more fit than the parent species in hybrid species habitats. Hybrid and parental species were reciprocally transplanted into hybrid and parental habitats. Helianthus anomalus was more fit than parental species in the H. anomalus actively moving desert dune habitat. The abilities to tolerate burial and excavation and to obtain nutrients appear to be important for success in the H. anomalus habitat. In contrast, H. deserticola failed to outperform the parental species in the H. deserticola stabilized desert dune habitat, and several possible explanations are discussed. The home site advantage of H. anomalus is consistent with environmental selection having been a mechanism for adaptive divergence and hybrid speciation and supports the use of H. anomalus as a valuable system for further assessment of environmental selection and adaptive traits.


Subject(s)
Ecosystem , Helianthus/genetics , Hybridization, Genetic/physiology , Adaptation, Physiological/genetics , Genetic Speciation , Selection, Genetic
16.
Ann Oncol ; 21(3): 608-614, 2010 Mar.
Article in English | MEDLINE | ID: mdl-19880433

ABSTRACT

BACKGROUND: Substantial numbers of cancer patients use complementary medicine therapies, even without a supportive evidence base. This study aimed to evaluate in a randomized controlled trial, the use of Medical Qigong (MQ) compared with usual care to improve the quality of life (QOL) of cancer patients. PATIENTS AND METHODS: One hundred and sixty-two patients with a range of cancers were recruited. QOL and fatigue were measured by Functional Assessment of Cancer Therapy-General and Functional Assessment of Cancer Therapy-Fatigue, respectively, and mood status by Profile of Mood State. The inflammatory marker serum C-reactive protein (CRP) was monitored serially. RESULTS: Regression analysis indicated that the MQ group significantly improved overall QOL (t(144) = -5.761, P < 0.001), fatigue (t(153) = -5.621, P < 0.001), mood disturbance (t(122) =2.346, P = 0.021) and inflammation (CRP) (t(99) = 2.042, P < 0.044) compared with usual care after controlling for baseline variables. CONCLUSIONS: This study indicates that MQ can improve cancer patients' overall QOL and mood status and reduce specific side-effects of treatment. It may also produce physical benefits in the long term through reduced inflammation.


Subject(s)
Affect , Breathing Exercises , Fatigue/therapy , Inflammation/therapy , Neoplasms/physiopathology , Quality of Life , Adult , Aged , Aged, 80 and over , C-Reactive Protein/metabolism , Case-Control Studies , Female , Health Status , Humans , Male , Middle Aged , Neoplasms/psychology , Outcome Assessment, Health Care , Prognosis , Surveys and Questionnaires
17.
AJNR Am J Neuroradiol ; 31(4): 761-6, 2010 Apr.
Article in English | MEDLINE | ID: mdl-19942694

ABSTRACT

BACKGROUND AND PURPOSE: ORN is a postradiation complication that has been well-documented in the medical literature. Most cases in the head and neck have been described in the mandible or larynx. Only a handful of cases in the hyoid bone are documented, all in the clinical literature. Our purpose is to present the clinical and imaging features of ORN involving the hyoid bone. MATERIALS AND METHODS: We present a case series of 13 patients with imaging findings highly suggestive of hyoid ORN after radiation therapy for head and neck cancers, in which we observed progressive features of hyoid disruption along with adjacent soft-tissue ulceration. RESULTS: Pretreatment imaging, when available, showed a normal hyoid. Typical postradiation imaging findings included an initial tongue base ulcerative lesion with air approaching the hyoid bone, and subsequent observation of hyoid fragmentation, often with intraosseous or peri-hyoid air and the absence of associated mass-like enhancement. CONCLUSIONS: Findings of hyoid fragmentation, cortical disruption, and soft tissue or intraosseous air in the postradiation therapy patient should strongly suggest the diagnosis of hyoid ORN. It is important recognize this entity because the diagnosis may preclude potentially harmful diagnostic intervention and allow more appropriate therapy.


Subject(s)
Carcinoma, Squamous Cell/radiotherapy , Hyoid Bone/radiation effects , Image Processing, Computer-Assisted , Osteoradionecrosis/diagnostic imaging , Otorhinolaryngologic Neoplasms/radiotherapy , Positron-Emission Tomography , Tomography, X-Ray Computed , Adult , Aged , Female , Humans , Hyoid Bone/diagnostic imaging , Male , Middle Aged , Pharynx/diagnostic imaging , Pharynx/radiation effects , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted , Retrospective Studies , Tongue/radiation effects
19.
New Phytol ; 183(3): 868-879, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19552693

ABSTRACT

Habitats that differ in soil resource availability are expected to differ for selection on resource-related plant traits. Here, we examined spatial and temporal variation in phenotypic selection on leaf ecophysiological traits for 10 Helianthus populations, including two species of hybrid origin, Helianthus anomalus and Helianthus deserticola, and artificial hybrids of their ancestral parents. Leaf traits assessed were leaf size, succulence, nitrogen (N) concentration and water-use efficiency (WUE). Biomass and leaf traits of artificial hybrids indicate that the actively moving dune habitat of H. anomalus was more growth limiting, with lower N availability but higher relative water availability than the stabilized dune habitat of H. deserticola. Habitats differed for direct selection on leaf N and WUE, but not size or succulence, for the artificial hybrids. However, within the H. anomalus habitat, direct selection on WUE also differed among populations. Across years, direct selection on leaf traits did not differ. Leaf N was the only trait for which direct selection differed between habitats but not within the H. anomalus habitat, suggesting that nutrient limitation is an important selective force driving adaptation of H. anomalus to the active dune habitat.


Subject(s)
Ecosystem , Helianthus/genetics , Helianthus/physiology , Plant Leaves/genetics , Plant Leaves/physiology , Quantitative Trait, Heritable , Selection, Genetic , Biomass , Hybridization, Genetic , Phenotype , Population Dynamics , Time Factors
SELECTION OF CITATIONS
SEARCH DETAIL